drm/radeon: handle vfct with multiple vbios images

commit a882f5de upstream.

The vfct table can contain multiple vbios images if the
platform contains multiple GPUs. Noticed by netkas on
phoronix forums.  This patch fixes those platforms.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/gpu/drm/radeon/radeon_bios.c

@@ -597,51 +597,57 @@ static bool radeon_read_disabled_bios(struct radeon_device *rdev)
 #ifdef CONFIG_ACPI
 static bool radeon_acpi_vfct_bios(struct radeon_device *rdev)
 {
-	bool ret = false;
 	struct acpi_table_header *hdr;
 	acpi_size tbl_size;
 	UEFI_ACPI_VFCT *vfct;
-	GOP_VBIOS_CONTENT *vbios;
-	VFCT_IMAGE_HEADER *vhdr;
+	unsigned offset;
 
 	if (!ACPI_SUCCESS(acpi_get_table_with_size("VFCT", 1, &hdr, &tbl_size)))
 		return false;
 	if (tbl_size < sizeof(UEFI_ACPI_VFCT)) {
 		DRM_ERROR("ACPI VFCT table present but broken (too short #1)\n");
-		goto out_unmap;
+		return false;
 	}
 
 	vfct = (UEFI_ACPI_VFCT *)hdr;
-	if (vfct->VBIOSImageOffset + sizeof(VFCT_IMAGE_HEADER) > tbl_size) {
-		DRM_ERROR("ACPI VFCT table present but broken (too short #2)\n");
-		goto out_unmap;
-	}
+	offset = vfct->VBIOSImageOffset;
 
-	vbios = (GOP_VBIOS_CONTENT *)((char *)hdr + vfct->VBIOSImageOffset);
-	vhdr = &vbios->VbiosHeader;
-	DRM_INFO("ACPI VFCT contains a BIOS for %02x:%02x.%d %04x:%04x, size %d\n",
-			vhdr->PCIBus, vhdr->PCIDevice, vhdr->PCIFunction,
-			vhdr->VendorID, vhdr->DeviceID, vhdr->ImageLength);
+	while (offset < tbl_size) {
+		GOP_VBIOS_CONTENT *vbios = (GOP_VBIOS_CONTENT *)((char *)hdr + offset);
+		VFCT_IMAGE_HEADER *vhdr = &vbios->VbiosHeader;
 
-	if (vhdr->PCIBus != rdev->pdev->bus->number ||
-	    vhdr->PCIDevice != PCI_SLOT(rdev->pdev->devfn) ||
-	    vhdr->PCIFunction != PCI_FUNC(rdev->pdev->devfn) ||
-	    vhdr->VendorID != rdev->pdev->vendor ||
-	    vhdr->DeviceID != rdev->pdev->device) {
-		DRM_INFO("ACPI VFCT table is not for this card\n");
-		goto out_unmap;
-	}
+		offset += sizeof(VFCT_IMAGE_HEADER);
+		if (offset > tbl_size) {
+			DRM_ERROR("ACPI VFCT image header truncated\n");
+			return false;
+		}
 
-	if (vfct->VBIOSImageOffset + sizeof(VFCT_IMAGE_HEADER) + vhdr->ImageLength > tbl_size) {
-		DRM_ERROR("ACPI VFCT image truncated\n");
-		goto out_unmap;
-	}
+		offset += vhdr->ImageLength;
+		if (offset > tbl_size) {
+			DRM_ERROR("ACPI VFCT image truncated\n");
+			return false;
+		}
 
-	rdev->bios = kmemdup(&vbios->VbiosContent, vhdr->ImageLength, GFP_KERNEL);
-	ret = !!rdev->bios;
+		if (vhdr->ImageLength &&
+		    vhdr->PCIBus == rdev->pdev->bus->number &&
+		    vhdr->PCIDevice == PCI_SLOT(rdev->pdev->devfn) &&
+		    vhdr->PCIFunction == PCI_FUNC(rdev->pdev->devfn) &&
+		    vhdr->VendorID == rdev->pdev->vendor &&
+		    vhdr->DeviceID == rdev->pdev->device) {
+			rdev->bios = kmemdup(&vbios->VbiosContent,
+					     vhdr->ImageLength,
+					     GFP_KERNEL);
+
+			if (!rdev->bios) {
+				kfree(rdev->bios);
+				return false;
+			}
+			return true;
+		}
+	}
 
-out_unmap:
-	return ret;
+	DRM_ERROR("ACPI VFCT table present but broken (too short #2)\n");
+	return false;
 }
 #else
 static inline bool radeon_acpi_vfct_bios(struct radeon_device *rdev)